CN1211887A - Advanced method for executing handover - Google Patents

Abstract

A cellular radio system comprises base stations and mobile stations. In order to execute handover, there is chosen a group of potential new base stations and estimated the carrier to interference ratio that each potential new base station included in said group could offer. The carrier to interference ratio can be estimated separately for real-time and for non-real-time connections and/or for uplink and downlink connections.

Description

Carry out the advanced method that switches

In general, the present invention relates in cellular wireless system, how to judge that mobile radio station switches to new base station.Specifically, relate to as the priority of how switching and set different base stations.

In cellular wireless system, a known so-called handoff procedure, according to this process, when the connection by old base station became too weak or too many interference is arranged, the route of selecting the transfer of data between the standing part of mobile radio station and system to be connected was passed through new base station.For example in gsm system (global system for mobile communications), each base station sends signal in given so-called BCCH channel (Broadcast Control Channel), in this situation, the power of the BCCH signal that this moving station measuring receives also determines that on this basis which mesh is best for this dedicated radio link.The BCCH frequency that the base station also notifies this mobile radio station to use in adjoining cells makes mobile radio station know which frequency they must intercept so that find the BCCH transmission of adjoining cells.

Fig. 1 represents second generation cellular system, comprises the moving exchanging center MSC of the nuclear network that belongs to cellular system, and the base station controller BSC and the base station BS that belong to Radio Access Network RAN; Mobile radio station MS is connected with described base station.Fig. 2 is illustrated in the area of coverage 201a-209a of the base station 201-209 in another second generation cellular system.

In second generation cellular system,, carry out transfer of data between base station BS and the nuclear network CN by the base station such as gsm system.Base station controller is a large amount of base station of control usually, makes that the base stations with new mesh two Geju City are typically connected to the same base controller when mobile radio station regional from the region shifting of a mesh to another mesh.At this moment can carry out the switching of work base station at this base station controller.Then, for example occurring seldom such mesh at mobile radio station when the base station of receiving first base station controller moves to the base station that is connected to second base station controller in normal gsm system switches.If this situation takes place, this switching center must should be connected and set up with new the new of base station controller and be connected with first base station controller closure.The process of this type comprises the many signalings between base station controller and the switching center, and because the distance between base station controller and the switching center may be grown, may occur disturbing between transfer period, and the two is relevant with base station and base station controller.

The arrangement of the base station of switch operating and the prior art of base station controller is well suited for so-called second generation digital cellular wireless system, such as GSM and extended version DCS 1800 (digital communication system of 1800MHz) thereof, IS-54 (interim standard 54) and PDC (personal digital cellular).But, advised at following third generation digital cellular wireless system, different significantly to this mobile radio station by mesh of mesh of quality of service that mesh provides.The suggestion of third generation system is UMTS (universal mobile telecommunications system) and FPLMTS/IMT-2000 (the international mobile communication of following public land mobile communication system 200MHz).In these schemes, they size and the basis of characteristic on mesh for example be divided into slightly, millimicro, little and grand mesh, and for example data transmission capacity can be used for narrating professional quality.The maximum data transmission capacity is provided with the minimum data transmission capacity by slight mesh and is provided by grand mesh.Mesh can be partially or completely overlapping, and may be different mobile terminal devices, and in this situation, the quality of service that is provided by all mesh can not be provided all mobile radio stations with needing.And the base station can support to require business real-time and the non-real-time data transmission in a different manner.

Fig. 3 represents a kind of following cellular wireless system of pattern, and for example it is not fully new for known gsm system, but comprises known unit and complete new unit.The bottleneck of cellular wireless system stops at present provides state-of-the-art business to mobile radio station, and this bottleneck is the radio access network RAN that is formed by base station and base station controller.The nuclear network of cellular wireless system comprises mobile services switching centre (MSC), other network element is (as being connected to the SGSN and the GGSN of packet radio transmission in GSM, be Serving GPRS Support Node and Gateway GPRS Support Node, the GPRS here is meant general packet wireless business) and receive the unit of their transmission system.According to the GSM+ definition that obtains from GSM, nuclear network also can send novel business.

In Fig. 3, the nuclear network of cellular wireless system 300 is GSM+ nuclear networks 301, and three parallel Radio Access Networks are coupled.Therein, network 302 and 303 is UMTS Radio Access Networks, and network 304 is GSM+ Radio Access Networks.The UMTS Radio Access Network that topmost is represented promptly 302 for example provides mobile communication business and serves the commercial Radio Access Network that described operator's user's all users' telecommunications operator has comparably.Below UMTS Radio Access Network 303 may for example be the wireless access network of the special use that has by enterprise, it is convenient to described wireless access mesh function.Mesh in the private radio access network 303 is millimicro and/or slight mesh typically, and the terminal that only has an employee of enterprise can be arranged in them.All three Radio Access Networks can comprise the mesh that different kinds of business and size variation are provided.And all three kinds of Radio Access Networks 302,303 and 304 mesh may be overlapping whole or in part.The bit rate of using every kind of situation depends on radio environment, professional characteristic, the regional total capacity of cellular wireless system and other user's the capacity needs of adopting.Above-mentioned novel radio access network is commonly referred to as general Radio Access Network (GRAN).Such network can be connected with dissimilar nuclear network CN cooperations and use, and GPRS network cooperation special and gsm system is used.General Radio Access Network GRAN may be defined as one group of such base station BS and their radio network controller (RNC) of control, and the quantity of this group can exchange message message.In the following description, general Radio Access Network abbreviates wireless network GRAN as.

Mobile radio station 305 shown in Fig. 3 is the double mode station of what is called the most advantageously, according to obtaining the sort of business and what transfer of data of user's needs in its region of the time point of being discussed, this mobile radio station can play a part second generation GSM terminal or third generation UMTS terminal.It also can be used as multi mode terminal, the mobile radio station that can play a part several different pieces of information transmission systems according to the needs and the possibility of business.The available business of mobile access network and user defines in subscriber identification module SIM306.

Fig. 4 represents the nuclear network CN of third generation cellular radio system in more detail, and CN comprises a MSC of switching center and receives the wireless network GRAN of nuclear network.Wireless network GRAN comprises radio network controller (RNC) and the base station BS that is connected.It is professional that now given radio network controller (RNC) and the base station that is connected can provide on broadband, and another radio network controller and connection the base station possiblely can only provide traditional narrow frequency business, still may have the big area of coverage.

Fig. 5 represents the area of coverage 501a-506a of base station 501-506 in the third generation cellular wireless system.As in Fig. 5, seeing, fixed terminal or even the terminal that moves of short distance can when setting up wireless connections, in several different base stations, select.

How the research of let us adjustment now prior-art devices is applied in the designed third generation digital cellular wireless system.In third generation system, the switching and the second-generation system of work base station and work radio network controller are more common.That is, wherein owing to the minimum and fact during wireless connections of mesh scale possibility, type of service wishes for example to change into the broadband from the arrowband.And require the beginning or the end of the miscellaneous service of real-time or non real-time transfer of data may influence the needs that change base station or base station controller.

In the mobile radio station prior art of received signal power level measure do not provide may be best how can respond the effect of the service needed of this mobile radio station about new base station.If often carry out the switching of base station and/or radio network controller, the new route of this connection is not possible best with respect to the service needed of mobile radio station after all, because unnecessary this network of switching is loaded.Switching center should carry out the connection cut-out/foundation of huge amount, and this requires a large amount of extra signalings between switching center and radio network controller.And, in a switching center zone, quite a large amount of small-scale mesh is arranged, and in broadband application, the quantity of the user data that send also is very big.This causes high capacity of switching center's equipment and rate request, when using present technology, can not realize in big system with rational expense.

The objective of the invention is to introduce the method and apparatus that is used to carry out switching, provide the possibility of the business of mobile radio station needs so that consider the base station.

By realizing purpose of the present invention with the potential new base station of prioritizing on the existing basis of loading of Carrier interference ratio level and base station that may provide in new base station.

The method according to this invention is characterized in that in order to select new base station, selects one group of potential new base station and estimation to belong to each available Carrier interference ratio in potential new base station of described group.

The invention still further relates to cellular wireless system, it is characterized in that: in order to select new base station, it comprises being used to estimate and belongs to the device that this organizes each available Carrier interference ratio in base station of potential new base station.

According to the present invention, estimation is undertaken by each potential new base station; This estimation is according to dominant interference level in having known the overall transmission power that uses this base station and this base station mesh areas, and the measuring-signal attenuation between base station and mobile radio station when knowing in the base station available idle data transport capacity.These estimations keep continuously, and the new base station of selecting is to estimate a best new base station according to this.Continue situation about back and forth switching between two such base stations of quite similar advantage in order to prevent mobile radio station having according to estimation, just only can require the estimation of new base station during above given threshold value of estimation of present base station this mobile radio station switch to new base station a hysteresis arranged.

Signal loss between base station and the mobile radio station calculates by considering the difference between the received power of the transmitted power of base station on given control or the pilot channel and corresponding mobile radio station.Identical transmitted power can be used in all base stations on control or pilot channel, and perhaps each base station can notify mobile radio station to use what power under any given situation.In order to stipulate the level of total transmitted power and interference power, given gross power parameter and given interference power parameter are calculated in each base station, and are how high at the C/I that obtains in up link and down link direction between base station and the mobile radio station than (Carrier interference ratio) in prediction on these bases.In addition, calculate the load coefficient of potential new base station with respect to real-time and non-real-time data transmission.In a preferred embodiment of the invention, whether the load parameter indication that is connected to real-time Data Transmission is the same with the data transmission capacity of reserving for this mobile radio station in base station at present big and be connected to the available much shares of distributing to the new base station data transmission capacity that non-real-time data transmits of the load parameter indication of non-real-time data transmission at the available data transmission capacity in new base station.

The estimation of describing new base station advantage by the C/I of prediction than and load parameter collect, all these preferably are connected separate computations to up link with down link.The differently weighting when forming estimation of up link and down link direction is if of wishing to emphasize to be used to switch or another direction is important.According to the present invention, the connection that requires real-time Data Transmission is towards the mesh that obtains best C/I ratio, and requires the mesh of the connection of non-real-time data transmission towards the C/I ratio with best all channel weighting, i.e. the maximum quantity of " free time " transmission of power.From the viewpoint of system operation, the present invention attempts to connect neutralization at each makes C/I than maximum at the same time, and therefore the feasible overall transmission power minimum of using is optimized and utilized available resource.

Illustrate in greater detail the present invention below with reference to several preferred embodiments that provides with example and accompanying drawing.

Fig. 1 represents known second generation cellular wireless system,

Fig. 2 represents according to some areas of coverage in the system of Fig. 1,

Fig. 3 represents the following form of cellular wireless system,

The details of Fig. 4 presentation graphs 3,

Fig. 5 represents some areas of coverage with the order shown in this system according to Fig. 3,

Fig. 6 represents the form of some parameters in the system according to the invention,

Fig. 7 represent in the preferred embodiments of the present invention signaling and

Fig. 8 represents the signaling in another preferred embodiment of the present invention.

In the above in the narration of prior art, we are with reference to Fig. 1-5, and below the present invention and preferred enforcement thereof in the narration, we are mainly with reference to Fig. 6-8.

Fig. 6 represents mobile radio station 600, and it receives by base station 601,602 and 603 signals, the particularly signal that sends on so-called BCCH channel of broadcast control that send.Given transmitted power is used in each base station in its BCCH sends, in this diagram with symbol Ptx-BCCHi mark, for base station 601,602 and 603 this subscript i values of obtaining 1,2 and 3.The signal that is sent by the base station is in a different manner at they road fading rises to mobile radio station 600, mobile radio station 600 with power P rx-BCCHi reception they, subscript i value of obtaining 1,2 and 3.Mobile radio station 600 calculates the path attenuation of each base station according to following formula: $L_i^{\mathrm{pl}}=\frac{{\mathrm{Prx}}_{-}{\mathrm{BCCH}}_i}{{\mathrm{Ptx}}_{-}{\mathrm{BCCH}}_i}---\left(1\right)$

Because path attenuation Li ^PLBe defined as ratio, it does not have unit.Should receive the knowledge of which BCCH transmission of base station about it, the mobile radio station 600 known current base station of mode from be included in its transmission obtain the peripheral base station of a tabulation.If the BCCH through-put power of base station is not constant in this system, then mobile radio station is also known the BCCH through-put power Ptx-BCCHi that is used by each base station in a known way.The candidate list of all such base stations of mobile radio station editor, the path attenuation of calculating are used for the so-called amount of switching surplus and are lower than (with parameter L i ^PLBe higher than) path attenuation that present base station is calculated.Should move the information signal that stations can be given this base station and further arrive the path attenuation of 604 measurements of radio network controller through the base station more.

In order to narrate total through-put power, calculate the downlink transmitted power parameter Ptxi of each base station according to following formula ^{Inv, down}: ${\mathrm{Ptx}}_i^{\mathrm{inv},\mathrm{down}}=\frac{1}{N}\underset{n,f}{\mathrm{\Σ}}\frac{1}{P_{n,f}}---\left(2\right)$

Substitute reverse frequency (inverted frequencywise) and time slot position (slotwise) power, can directly use this power according to following formula: ${\mathrm{Ptx}}_i^{\mathrm{down}}=\frac{1}{N}\underset{n,f}{\mathrm{\Σ}}{P}_{n,f}---\left(2a\right)$

(2) the transmission power parameters Ptxi that defines in the formula ^{Inv, down}Unit be W ^-1, and transmission power parameters Ptxi ^DownUnit be W.Here we suppose that the downlink transmission of each base station is to have the frame of time slot and the compiling of frequency, so Pnf is the through-put power of using in the time slot n of frequency f.Then by the definition of this time slot and frequency, be included in the total number of timeslots N in this frame.Therefore, we get the reciprocal and addition of the power that sends in each time slot in (2) formula, afterwards should and divided by the time slot sum.According to another preferred embodiment, also can calculate each time slot respectively according to the value of (2) formula; This method is particularly suitable for not using the system of time slot jump.

In order to narrate total interference level, also calculate according to following formula $I_i^{\mathrm{inv},\mathrm{up}}=\frac{1}{N}\underset{n,f}{\mathrm{\Σ}}\frac{1}{I_{n,f}}---\left(3\right)$ As another scheme, even can use following formula according to reverse frequency power now: $I_i^{\mathrm{up}}=\frac{1}{N}\underset{n,f}{\mathrm{\Σ}}{I}_{n,f}---\left(3a\right)$

Interference power parameter I i ^{Inv, up}Unit also be W ^-1With the interference power parameter I i that substitutes ^UpThe unit be W.Therefore in (3) formula, measure the reciprocal value of the interference power that during each uplink time slot, receives, resulting afterwards reciprocal value addition, and should and divided by the time slot sum.According to above-mentioned second embodiment, also can calculate a value dividually to each time slot according to (3) formula.

When according to (2) formula and (3) formula calculated value, the detected dl interference power of this mobile radio station in the mesh of new base station can be estimated in each base station.According to following formula with the W of unit ^-1Estimation dl interference power Ii ^{Inv, down}: $I^{\mathrm{inv},\mathrm{down}}=\underset{i=1}{\overset{M}{\mathrm{\Σ}}}\frac{{{\mathrm{Ptx}}_i}^{\mathrm{inv},\mathrm{down}}}{L_i^{\mathrm{pl}}}---\left(4\right)$ M is included in the so new base station number in the candidate list in the formula, and the new base station of these that estimate is with the transmission frequency work identical with estimating new base station.And alternate form is a following formula: $I^{\mathrm{down}}=\underset{i=i}{\overset{M}{\mathrm{\Σ}}}{\mathrm{Ptx}}_i^{\mathrm{down}}\·L_i^{\mathrm{pi}}---\left(4a\right)$

Now we can according to following formula estimation in the mesh of new base station mobile radio station can detected down link C/I than (with subscript i mark): ${(C/I)}_i^{\mathrm{down}}={\mathrm{Ptx}}^{\mathrm{down}}\·L_i^{\mathrm{pi}}\·(I^{\mathrm{inv},\mathrm{down}}-\frac{{\mathrm{Ptx}}_i^{\mathrm{inv},\mathrm{down}}}{L_i^{\mathrm{pl}}})---\left(5\right)$ Obtain following formula according to replacing us: ${(C/I)}_i^{\mathrm{down}}=\frac{{\mathrm{Ptx}}^{\mathrm{down}}\·L_i^{\mathrm{pl}}}{(I^{\mathrm{down}}-{\mathrm{Ptx}}_i^{\mathrm{down}}\·L_i^{\mathrm{pl}})}---\left(5a\right)$

C/I is than no unit, because it is a ratio.Do not descend aiming symbol Ptx here ^DownBe used to be illustrated in the transmitted power that use present base station when mobile radio station sends.

Correspondingly, can estimate from following formula with the up link C/I ratio in the mesh of new base station of subscript i mark: ${(C/I)}_i^{\mathrm{up}}={\mathrm{Ptx}}^{\mathrm{up}}\·L_i^{\mathrm{pl}}\·(I^{\mathrm{inv},\mathrm{up}}-\frac{{\mathrm{Ptx}}_i^{\mathrm{inv},\mathrm{up}}}{L_i^{\mathrm{pl}}})---\left(6\right)$ Unsubscripted symbol Ptx in the formula ^UpBe illustrated in the transmitted power that mobile radio station uses when present base station sends.As an alternative, we obtain following formula: ${(C/I)}_i^{\mathrm{up}}=\frac{{\mathrm{Ptx}}^{\mathrm{up}}\·L_i^{\mathrm{pl}}}{(I^{\mathrm{up}}-{\mathrm{Ptx}}_i^{\mathrm{up}}\·L_i^{\mathrm{pl}})}---\left(6a\right)$

The alternative formula that provides above is to substitute according to the principle that must only use 2-6 formula 2a-6a formula.

In order to narrate the base station attenuation, can use many different definition.We have found that it is favourable that the business that requires real-time Data Transmission is used the load parameter of the quantity that is described in the available data transmission capacity in base station respectively with the business that requires the non-real-time data transmission.Let us utilizes following formula to define the load parameter fi of relevant non-real-time data transmission ^NRT: $f_i^{\mathrm{NRT}}=\frac{C_{\mathrm{tot}}-C_{\mathrm{tot}}^{\mathrm{RT}}}{U_i^{\mathrm{NRT}}+1}---\left(7\right)$

C in the formula _TotBe the highest possible timeslot number in the frame structure that uses at present, C _Tot ^RTIt is the timeslot number of distributing to real-time Data Transmission between in these.Frame structure for example can conform to the structure introduced in the corresponding Application No. 802645 of Finnish patent application numbers 964308 and application on February 19th, 1997, therefore is included in wherein number of timeslots and variable sizeization.Unlikely fuzzy in order to guarantee, the C coefficient that occurs in the formula (7) has represented that advantageously therefore the unit that adopts is the minimum time slot size that allows, and for example may be 1/64 of frame capacity.In formula (7), symbol Ui ^NRTExpression is by the quantity of effective non real-time carrier of described base station.The notion here " carrier " is meant the entity that is made of all this coefficients that influence the transfer of data between base station and the given mobile radio station.Notion " carrier " is comprising data transmission rate, delay and the error rate and the fluctuation of these coefficients in given minimum and maximum.Carrier can be regarded as the data transfer path of setting up owing to the combined effect in the described path of all these coefficients, connection base station and given mobile radio station, and can send useful data by this path, i.e. Payload information.Multi-functional mobile radio station can keep connecting the several carriers of this mobile radio station to one or several base station simultaneously.

The load parameter fi of relevant real-time Data Transmission ^RTDefine by following formula:

S is the timeslot number of reserving for the mobile radio station that is connected with present base station in the formula.Coefficient S must provide with the unit identical with the C coefficient.Load parameter according to formula (7) and (8) can define up link and down link direction dividually, make that C coefficient and the overall coefficient of heat transfer in (7) formula only is applied in the transmission direction of being discussed in formula, and load coefficient there are an extra subscript " up " or " down ".

According to the present invention, for accepted those base stations of candidate list on the path attenuation based measurement, calculate an estimation, the base station is estimated with mutual prioritizing according to this.The C/I ratio of applied load coefficient and estimation in calculating this estimation.Being used to calculate the favourable formula of estimating Wi in full base station is: $W_i={10\log }_{10}(\[f_i^{\mathrm{RT},.\mathrm{down}}\·f_i^{\mathrm{NRT},\mathrm{down}}\•{(C/I)}_i^{\mathrm{down}}{\]}^2\•\[f_i^{\mathrm{RT}.\mathrm{up}}\•f_i^{\mathrm{NRT}.\mathrm{up}}\•{(C/I)}_i^{\mathrm{up}}{\]}^b)---\left(9\right)$ Obtain the value Wi that represents with decibel.By selecting power time a and b, stipulate mainly for which transmission direction of selection (up link or down link) of new base station, perhaps two transmission directions are of equal importance.Without a and b, time available formula (1+a/64) of the every power in the formula (9) in the square brackets and (1-a/64) definition, number a is an integer in scope (64,64).Therefore we obtain higher precision, if particularly be used for representing it keep the situation of limited quantity bit count a very much must be from a terminal of cellular wireless system in another terminal of message signaling.The inferior desired value of power can find by test.

Its principle is to select to have the base station of estimation Wi of the highest calculating as new base station.In order to prevent that mobile radio station from back and forth switching between two the such base station i of the estimation Wi of the calculating with equal value and Wj and j, its high H decibel of estimation that estimation that the base station calculates must be calculated than present base station of must looking for novelty, the H here is the arithmetic number outside 0.Another may be to comprise that the motion relevant with the time is average in than estimation in the calculating of path attenuation and/or at C/I, and this has reduced the possibility that two base stations obtain identical result.

In the superincumbent explanation, our also undeclared calculating and estimation that in those parts of cellular wireless system, realizes by system requirements.Path attenuation is measured and is the most advantageously carried out in mobile radio station, because the base station sends BCCH signal or corresponding signal regularly with known transmitted power, so path attenuation is measured easily on this basis.Calculating according to formula (2) and (3) is the most advantageously undertaken by the base station, because they know frame structure and the transmitted power of using in its different time-gap.Similarly, in the base station, be easy in conjunction with a measuring receiver, measuring receiver is measured the desired reception interference power of formula (3) during the different time-gap of frame structure.As can carrying out in radio network controller, nature is under the prerequisite of radio network controller signaling measurements and calculations information at mobile radio station and base station according to the calculated example of formula (4)-(9).After calculating this estimation according to formula (9), controller sends switching command through certain base station to mobile radio station when needed.

Calculating according to formula (4)-(9) also can be carried out in this mobile radio station, but this requires quite a large amount of calculated capacity of mobile radio station.And, also can in certain base station, carry out according to the calculating of formula (4)-(9), but this requires between the base station signaling quite widely.Nature, cellular wireless system also can be equipped in above-mentioned certain not shown equipment; The task of this equipment is to receive the signaling of relevant measurement result and calculate according to formula (4)-(9), and provides and carry out the order of switching.

The present invention does not require in conjunction with each switches calculating and the estimation of using all narrations.If switching parts in the cellular wireless system of relevant calculation is loaded and makes and can not carry out all calculating, carry out relevant simple certain other reason (for example potential new base station number has only) of judging of switching if perhaps have, then the judgement of new base station even can only on the path attenuation based measurement, carry out.

Then we should observe in carried out according to the example embodiment of the calculating of formula (4)-(9) by radio network controller the signaling needs according to Fig. 7.When the path attenuation condition changing or after base station BS sends order 702 for this reason, mobile radio station MS carries out with given interval and receives the received power measurement 701 that path attenuation calculates.For example after detected transmission power or interference power situation (formula (2) and (3)) variation, the base station can send described order 702.The result who measures, mobile radio station is given the base station and is further sent the measurement message 703 of the measurement data that is included in all base stations in the candidate list to radio network controller (RNC) by it.The base station can be ordered the possible measuring command 702 of mobile radio station execution route attenuation measurement to comprise relevant which base station and is included in information in the candidate list.When the base station has sent measurement message 703 to radio network controller, radio network controller sends switching command 704 to mobile radio station when needed, switching command 704 comprises all information of mobile radio station needs in known manner, so that begin transfer of data with new base station.Mobile radio station or process base station old or that process is new sends acknowledgement message 705 to radio network controller and confirms these switching commands.

Fig. 8 represents signaling in another embodiment, and wherein mobile radio station begins to switch.Through the BCCH channel that the base station that is included in the candidate list sends, mobile radio station obtains the information 802 by the transmitted power of base station execution and interference power measurement.If the mobile radio station decision is carried out switch, it sends message 803 through this base station to radio network controller for this reason.Radio network controller sends an acknowledgement message 804, it or accept or refuse this switching.

Under the situation that mobile radio station is lost suddenly with present base station is connected or in the mobile radio station start, and it is not when having current base station, then connects between that base station of the strongest BCCH signal of mobile radio station and transmission or corresponding signal.

As conclusion, following table comprises all such information, and these information (decision of switching is carried out in mobile radio station or in radio network controller) in method according to a preferred embodiment of the invention send as the signaling between mobile radio station, base station and base station controller.

From the base station to the mobile radio station	The time of signaling
		Switch the transmitted power Ptxi of the acknowledgement message BCCH channel of surplus (dB) candidate set command execution switching inv,dowmOr Ptxi down	The beginning that connects for example transmitted power or jamming power situation (formula (2) and (3)) change with switch relevant and switching about normally on the BCCH channel normally on the BCCH channel

?Ii inv,upOr Ii up	Normally on the BCCH channel
		The acknowledgement message that the reception BCCH power of present mesh begins switching at the BCCH of the reception of other mesh of candidate list power speed of mobile station from the movement station to the base station	The time of signaling normally in grouping normally/after base station requests/after power changes normally/after base station requests/relevant with switching relevant with switching rate variation after
From the base station to radio network controller Ptxi inv,downOr Ptxi downIi inv,upOr Ii up	The time of signaling for example with 100ms at interval for example with 100ms at interval

For those skilled in the art is conspicuous, and the buzzword of using above only is used to show of the present invention may the application such as " BCCH channel ", and they in no case limit the present invention.

Claims (10)

1. in the cellular wireless system that comprises base station and mobile radio station, carry out the method for switching, it is characterized in that, select one group of potential new base station and estimation to be included in each available Carrier interference ratio in potential new base station in described group in order to select new base station.

2. according to the method for claim 1, it is characterized in that estimating dividually and be included in the Carrier interference ratio that each potential new base station in described group can offer the connection that requires real-time Data Transmission and can offer the Carrier interference ratio that requires the non-real-time data transmission to be connected with each potential new base station.

3. according to the method for claim 1, it is characterized in that estimating dividually and be included in each potential new base station in described group and can offer the Carrier interference ratio that up link connects and to offer the Carrier interference ratio that down link is connected with each potential new base station.

4. according to the method for claim 1, it is characterized in that also measuring the load condition that is included in each potential new base station in described group.

5. according to the method for claim 4, it is characterized in that measuring dividually at uplink direction and be included in the load condition of each the potential new base station in described group and be included in the load condition of each the potential new base station in described group in the down link direction.

6. according to the method for claim 4, it is characterized in that measuring dividually and to require real-time Data Transmission to connect relevant, the load condition that is included in each the potential new base station in described group be connected load condition relevant, that be included in each potential new base station in described group with asking the non-real-time data transmission.

7. according to the method for claim 4, it is characterized in that each the potential new base station that is included in described group is estimated, load condition and selected new base station that available Carrier interference ratio in described base station and described base station are described in described estimation are to have the base station of favourable estimation.

8. a cellular wireless system that comprises base station and mobile radio station is characterized in that it comprises: in order to select new base station, be used to estimate the device of the available Carrier interference ratio in potential new base station of the potential new base station that belongs to given group.

9. cellular wireless system according to Claim 8 is characterized in that it comprises:

In mobile radio station, be used to measure this mobile radio station and at present the path attenuation between base station and this potential new base station device and be used for the device of measurement result that the path attenuation of this measurement is described in this base station of signaling,

In the base station, be used for describing power that this base station sends and power parameter reception interference power device and signal to radio network controller and/or this mobile radio station notify described power parameter device and

In radio network controller, being used to carry out about the Carrier interference ratio that corresponding base station can provide for this mobile radio station should be the device of the estimation of how high base station scope.

10. according to the cellular wireless system of claim 9, it is characterized in that it also comprises: in this base station, be used to measure this base station load and signal to the metrical information that this radio network controller notice is described described load.

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